1. Technical Field
This invention relates generally to a magnetic security switch for use with alarms and more particularly to a high security magnet switch for limiting defeat of the switch.
2. State of the Art
Prior art security alarm systems often make use of magnetic switches attached to doors and windows and integrated with the system for detecting unauthorized openings. One common type of magnetic switch used in these situations is a so-called reed switch. It has been found that reed switches are subject to unauthorized manipulation through use of an external magnet. Specifically, an intruder can hold a relatively strong magnet adjacent the reed switch which will then be operated (to either open or close depending on the control scheme). With this accomplished, an intruder can open the door or window without triggering the alarm system.
A number of magnetic switches have been proposed in the past to overcome the inherent deficiencies of reed switches. U.S. Pat. Nos. 6,506,987; 5,997,873; 5,530,428; 5,332,992; 5,673,021; and 5,880,659 describe switches of this type.
Each of these switches has its limitations, particularly in limiting the ability of an intruder to defeat the switch. Accordingly, there is a need for an improved high security switch.